There is a need for improved antiparasitics, and in particular there is a need for improved insecticides and acaricides, particularly for use in animal health. Furthermore, there is a need for improved topical and oral products with convenient administration. Still further, there is a need for improved compositions which contains one or more active antiparasitics, which can be used to effectively treat against parasites. Such improvements would be particularly useful for the treatment of animals including: birds (e.g., chickens and turkeys), fish, companion animals (e.g., cats, dogs, llamas, and horses), and livestock (e.g., cattle, bison, swine, sheep, deer, elk, and goats).
Currently available insecticidal and acaricidal treatments for animals do not always demonstrate good activity, good speed of action, or a long duration of action. Most treatments contain hazardous chemicals that can have serious consequences, including neurotoxicity and lethality from accidental ingestion. Persons applying these agents are generally advised to limit their exposure. Pet collars and tags have been utilized to overcome some problems, but these are susceptible to chewing, ingestion, and subsequent toxicological effects to the animal. Thus, current treatments achieve varying degrees of success, which depend partly on toxicity, method of administration, and efficacy. Additionally, some currently available agents are becoming ineffective due to parasitic resistance.
Despite the availability of effective, broad spectrum antiparasitics, there remains a need for safer and more convenient, efficacious, and environmentally friendly products that will overcome the ever-present threat of resistance development.
PCT/US2016/013358, herein incorporated by reference in its entirety, describes isothiazoline spiroazetidinyl-isobenzofuran derivatives which are demonstrated to be effective, broad spectrum antiparasitics. More specifically, the isothiazoline spiroazetidinyl isobenzofuran derivatives, including pesticidal, veterinary, or pharmaceutically acceptable salts thereof, are represented by Formula (I):

wherein each R1A, R1B, and R1C individually is hydrogen, alkyl, halogen, or haloalkyl; R2 is haloalkyl; X is bond, C(O), SO2, or C(O)NH; R3 is hydrogen, optionally substituted alkyl, optionally substituted haloalkyl, optionally substituted cycloalkyl, optionally substituted heterocyclyl, optionally substituted aryl, and optionally substituted heteroaryl, or a pesticidal, veterinary, or pharmaceutically acceptable salt thereof. One embodiment described is a compound 1-[6-[5-(3,5-dichloro-4-fluoro-phenyl)-5-(trifluoromethyl)-4H-isothiazol-3-yl]spiro[1H-isobenzofuran-3,3′-azetidine]-1′-yl]-3,3,3-trifluoro-propan-1-one, or a pesticidal, veterinary, or pharmaceutically acceptable salt thereof.